A Quasi-Resonant Current-Fed Converter With Minimum Switching Losses

A quasi-resonant dc-dc converter with high voltage gain and low current stresses on switches is proposed in this paper. This converter preserved inherent advantages of current-fed structures, for instance, zero magnetizing dc offset, low input ripple, and low transformer turn ratio. Moreover, by employing the active-clamp circuit, the voltage spikes across the main switch, due to the existence of leakage inductance of the isolating transformer, is absorbed, and switches work in zero voltage switching. Since quasi-resonant switching strategy is employed, turn-off current (TOC) and losses of switches are considerably reduced. Because of zero current switching (ZCS), reverse recovery problem of diodes is alleviated. Experimental results on a 150-W prototype are provided to validate the proposed concept.